Glad to know someone else gets worried about re-entering China. You have no problem.
Rest assured - your Residence Permit will get you in as many times as you like during its currency.
re. the money thing. Times do change! My first reaction was that there was no way you could use a China debit card in another country. The information from randyjet put me right on that.
After that I was rather dubious about the integrity of the system - would you trust all the hype to deliver the dollars when standing in front of an ATM in the USA? From what I can see (esp on Wikpedia, which mentions US Citibank specifically) it seems that the answer is that I should.
The Union Pay site notes that:
"Nearly 90% of the ATM machines in USA accept Unionpay debit card for USD cash withdrawal."
It also notes a daily limit of RMB10,000.That kind of limit is never going to trouble me!
Again, from the 'times have certainly changed department' I would not worry about the RMB side of the deal. I would worry that the US banking system collapsed while I was trying to locate a Citibank ATM.
That is because I am neurotic about banks.